Saudi Arabia has now sent the clearest of signals: it will fight to defend the old Arab social order over which it presides. Abdullah is Metternich, or should I say Brezhnev?

This was already rather clear from Saudi Arabia’s recent adventure suppressing Houthi dissidents in Yemen who could be seen as representing the first wave of the Yemeni people’s demand for justice. But the murky nature of Yemeni politics, with its overlapping civil wars and all the rush to exploit an alleged al Qua’ida presence (which is, be it real or not, a very valuable thing for all sorts of political interests), suggested that Riyadh’s Yemeni adventure might have been a one-off thing. But no, we now can see that it was the beginning of the new police of enforcement.

For Saudi Arabia to adopt a policy of enforcing its preeminence constitutes a decision with a long and ominous tail. One might, way back in mid-February, have imagined a new Mideast in which Arabs would suddenly join hands and move forward, leading the whole world toward a better future. Such a joint approach would have avoided both revolutionary violence and counter-revolutionary violence. It would also have marginalized all those forces, be they local extremists, Iranian instigators, or Western/Israeli empire-builders, that might have been looking for opportunities to make trouble. Such a new Mideast would have included such steps as:

Saudi reforms to address Saudi Shi’i concerns in the context of addressing the concerns of all Saudis chafing under Saudi Arabia’s harsh laws;

Bahraini accommodation of Bahraini Shi’i demands for participation in their country’s politics;

Protection of Libyan protesters from military attack;

Termination of the Israeli policy of collective punishment of the residents of the Gaza Ghetto;

A focus by temporary military regimes on managing a peaceful transition to civilian rule, with decisions about fundamental constitutional changes left for judicious consideration in the free marketplace of ideas rather than being rushed through by illegitimate temporary rulers in smoke-filled rooms.

But, alas, hopes for that new Mideast today appear a bit naïve.

Instead, Riyadh has chosen a road that threatens to split Mideast Arabs into two warring camps: old dictators armed with utterly gross quantities of Western arms against an angry but idealistic population that was desperately hoping for some signs of decency from its various governments. Foreign militarism and domestic oppression are two sides of the same coin, and, sure enough, Riyadh’s Bahraini adventure is reflected in its uncompromising rejection this week of domestic freedom of speech. This is a recipe either for chaos or stuffing the population back in the political pressure cooker, slamming the lid on tight, and turning up the heat.

Expect many cooks in the kitchen: some will manufacture incidents as excuses to intervene, some will get invitations from a neighboring state’s crooked politicians and then use that invitation as an excuse to commit murder, some will offer funds or soldiers or “look the other way” as mercenary gangs are hired, many will see an opportunity to clamp down on domestic dissent, and everyone on the outside will look for clients to support in the coming power struggle.

With a Saudi military intervention, Bahrain’s political crisis has been transformed into an international political crisis. The first consequence is that Bahraini protesters will be tempted to turn to violent resistance, as any population might be in the face of foreign boots on the ground. Second, Iran now has justification for making a military countermove to support Bahraini Shi’a. Third, any state—such as Israel—that might want to support Gaddafi now has the perfect precedent to “justify” such behavior. Fourth, all actors using force, such as Gaddafi and Saleh, now have encouragement to continue doing so, and all the rest will find the temptation to do so more difficult to resist.

The Egyptian military has been visibly teetering on a precipice for weeks, oppressing protesters one minute, compromising with them the next, and it faces an immediate decision of crucial importance for democracy in Egypt: to postpone a rushed vote on constitutional amendments or to push it through. The Saudi decision to use force facilitates the same choice by all regional actors.

The result is likely to be a surge in activity by Iran, Israel, and al Qua’ida, as all three rush to exploit new opportunities and to defend their interests. If Western powers are not already on the ground trying to manage events and protect access to oil, the mess created by Iranian, Israeli, and al Qua’ida interference will surely stimulate them to get involved. But none of these actors understands what is happening in the Arab world. Tehran, busy oppressing its own dissidents, can hardly appreciate the desires of Arabs for civil liberties. Tel Aviv is completely in denial, incapable of seeing the opportunity it has for fundamentally transforming its policy toward Palestinians as a means of opening the door to cooperation with a revolutionary Arab movement that is not yet anti-Israeli but very soon will be. Al Qua’ida, with its dreams of a Caliphate, is if anything even more utterly out of tune with the aspirations of the modernizing Arab generation now coming of age. And Western politicians, when they can see past the blinders put over their eyes by right-wing Israeli expansionists with dreams of their own Jewish equivalent of the Caliphate, see only oil.

The simultaneous, energetic interference of all these ignorant external actors in Arab politics will, should it occur, be messy and expensive—for everyone. Saudi military intervention in Bahrain is not a move for stability. It is a move for reaction. It is a step toward denial of popular aspirations and retrenchment. It encourages every politician tempted to put his career first, the long-term interests of the population second. It is a step away from the joy of Tahrir Square after Mubarak’s resignation and toward a zero-sum process of confrontation in which both sides become radicalized and all those outsiders begin finding opportunities to get involved. The result threatens to be political confusion beyond the ability of any actor to understand.

Riyadh’s little military adventure in Bahrain is just one step; Riyadh could still step back. But politicians have a hard time stepping back nimbly enough to avoid tripping: the ground seems always to be moving under their feet. That Riyadh made this move, even if the troops do nothing but have tea with the neighbors and then return home, will still have changed the regional political balance, and so today compromise is just a little bit harder than it was yesterday.